The purpose of this field investigation is to examine psychological and social effects of participation in competitive youth sports. The first objective is to determine the effects of various intra-personal and situational factors on the perception of threat to self in the competitive sport situation. The primary independent variables include competition trait anxiety and success-failure. The response to perceived threat is assessed by state anxiety and self-protective causal attribution. The second objective of this investigation is to determine intra-personal variables that mediate positive and negative self-esteem change among children participating in youth sports. Two sets of variables are examined. The first set focuses on the relationship between social acceptance by teammates and self-esteem change. The second set examines the relationship between task competence and self-esteem change. Subjects are 140 boys between 10 and 12 years of age participating in competitive youth soccer through the American Youth Soccer Organization. Pre-season measures of competition trait anxiety, basal state anxiety, self-esteem and task competence will be obtained. Pre-and post- game state anxiety will be assessed, as will post-game causal attributions. Sociometric questionnaires measuring liking and leadership choices among teammates will be administered throughout the season. Finally, post-season self-esteem will be measured.